Some duck egg yolks are orange while others are yellow.
Does that reflect the egg quality?
The following applies to poultry eggs in general, not specifically duck eggs.
Where does the colour come from?
Egg yolks get their colour from carotenoids. Carotenoids are plant
pigments, responsible for red, orange and yellow hues in certain
vegetables and fruits. You might guess then that carrots, pumpkins,
peppers, Vietnamese gac fruit, and sweet potatoes are all particularly
rich in carotenoids.
But carotenoids are also found in green plant material, because
carotenoids absorb light for photosynthesis and protect the plant from
What affects the colour?
It depends on what the poultry eats.
There are two classes of carotenoids:
- Carotenes, which tend to produce reddish colours, and
- Xanthophylls, which produce yellow shades.
Farmers can adjust yolk colour through the chickens’ diet. Small scale
farmers can directly feed plant material naturally high in carotenoids
(e.g. algae, alfalfa, citrus peel, fortified corn), while larger-scale
farmers rely on processed feed that contains such ground-up plant
material or synthetic supplements.
Processed poultry feed is a blend of grain, protein, vitamins and
minerals. In Europe, the EU Register of Feed Additives lists which
xanthophylls and carotenes can be added. So, a large-scale farmer has
to strike the right balance of yellow and red carotenoids to keep the
shade consistent. The types and ratios of carotenoids in feed and eggs
will depend on what yolk colour consumers want, and farmers provide.
Source: Orange Egg Yolks: Why Are Some Egg Yolks So Orange?